/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.solr.client.solrj.io.eval;

import java.io.IOException;
import java.math.BigDecimal;
import java.math.MathContext;
import java.util.Locale;
import org.apache.solr.client.solrj.io.stream.expr.StreamExpression;
import org.apache.solr.client.solrj.io.stream.expr.StreamFactory;

public class DivideEvaluator extends RecursiveNumericEvaluator implements TwoValueWorker {
  protected static final long serialVersionUID = 1L;

  public DivideEvaluator(StreamExpression expression, StreamFactory factory) throws IOException {
    super(expression, factory);

    if (2 != containedEvaluators.size()) {
      throw new IOException(
          String.format(
              Locale.ROOT,
              "Invalid expression %s - expecting two values but found %d",
              expression,
              containedEvaluators.size()));
    }
  }

  // override to give a slightly better error message than the default
  @Override
  public Object doWork(Object... values) throws IOException {
    if (2 != values.length) {
      String message = null;
      if (1 == values.length) {
        message =
            String.format(
                Locale.ROOT,
                "%s(...) only works with a 2 values (numerator,denominator) but 1 was provided",
                constructingFactory.getFunctionName(getClass()));
      } else {
        message =
            String.format(
                Locale.ROOT,
                "%s(...) only works with a 2 values (numerator,denominator) but %d were provided",
                constructingFactory.getFunctionName(getClass()),
                values.length);
      }
      throw new IOException(message);
    }

    return doWork(values[0], values[1]);
  }

  @Override
  public Object doWork(Object first, Object second) throws IOException {
    if (null == first) {
      throw new IOException(
          String.format(
              Locale.ROOT,
              "Unable to %s(...) with a null numerator",
              constructingFactory.getFunctionName(getClass())));
    }

    if (null == second) {
      throw new IOException(
          String.format(
              Locale.ROOT,
              "Unable to %s(...) with a null denominator",
              constructingFactory.getFunctionName(getClass())));
    }

    BigDecimal numerator = (BigDecimal) first;
    BigDecimal denominator = (BigDecimal) second;

    if (0 == denominator.compareTo(BigDecimal.ZERO)) {
      throw new IOException(
          String.format(
              Locale.ROOT,
              "Unable to %s(...) with a 0 denominator",
              constructingFactory.getFunctionName(getClass())));
    }

    return numerator.divide(denominator, MathContext.DECIMAL64);
  }
}
